I would not hesitate between 5070P and MB a second and go for 5070P.
MB is very very nice but like Bruno said, there's nothing special in the case design. Based on the looks, MB beats easily 5170 but I suppose the latter is technically more sophisticated. Furthermore, it's WG vs. steel. We should naturally compare RG vs. WG. My business professors always said: "don't compare apples with oranges".
I will travel soon to Singapore and try to make a visit to MB Boutique. If they have space in their order book, I might go for this nice new reference in steel.
Best, Kari